A Discrete Model for Nonequilibrium Growth Under Surface Diffusion Bias

TL;DR

This paper introduces a simple discrete model for nonequilibrium surface growth under diffusion bias, revealing that mound coarsening is transient and asymptotic growth follows a universal exponent, challenging existing continuum theories.

Contribution

The paper presents a novel limited mobility discrete model that captures complex surface morphologies and demonstrates the transient nature of mound coarsening under surface diffusion bias.

Findings

Mound coarsening is only transient at finite bias.

Asymptotic growth exponent is 0.5 in 1+1 and 2+1 dimensions.

Simulation results differ from existing continuum growth equations.

Abstract

A limited mobility nonequilibrium solid-on-solid dynamical model for kinetic surface growth is introduced as a simple description for the morphological evolution of a growing interface under random vapor deposition and surface diffusion bias conditions. Simulations using a local coordination dependent instantaneous relaxation of the deposited atoms produce complex surface mound morphologies whose dynamical evolution is inconsistent with all the proposed continuum surface growth equations. For any finite bias, mound coarsening is found to be only an initial transient which vanishes asymptotically, with the asymptotic growth exponent being 0.5 in both 1+1 and 2+1 dimensions. Possible experimental implications of the proposed limited mobility nonequilibrium model for real interface growth under a surface diffusion bias are critically discussed.